With the rapid growth of the information industries, various information-processing systems have recently been developed and recording techniques and apparatuses suited for each information-processing system have been developed and adopted. Thermal transfer recording, which is one such recording technique, is advantageous in that the equipment therefor is light-weight, compact, and noiseless and its operation and maintenance are easy. Further, this recording technique is easily applicable to color recording, and it has consequently been extensively used in recent years.
This thermal transfer recording technique is roughly divided into two types, a thermal fusion type and a thermal transfer type. In the latter technique, a thermal transfer dye-donating material comprising a support having a dye-donating layer containing a binder and a heat-transfer dye is superposed on a thermal transfer image-receiving material. Heat is applied from the support side of the dye-donating material, thereby transferring the heat-transfer dye to the recording medium (thermal transfer image-receiving material) in accordance with the heat pattern applied to obtain a transferred image.
The heat-transfer dye discussed is a dye which can transfer from a thermal transfer dye-donating material to a thermal transfer image-receiving material by means of sublimation or diffusion into the medium.
However, the thermal transfer image-receiving material used in the thermal transfer recording techniques of this type has the following problems. When the thermal transfer image-receiving material is superposed on a thermal transfer dye- donating material and the heat-transfer dye is transferred to the image-receiving material by heat application, the two materials are fused often to each other and, as a result, difficulties are encountered in peeling the two materials from each other after thermal transfer. Additionally, there are cases in which even if the two materials are readily peeled from each other, the surface layer of the dye-donating material been coated with the dye-donating layer adheres to the image-receiving material surface, resulting in impaired image quality or making the conveyance of the image-receiving material within the printer difficult. This trouble arises frequently, particularly when thermal transfer is conducted at an increased applied voltage and an elevated temperature in order to obtain a sufficient transfer density.
Further, there is another problem that when the thermal transfer image-receiving material is not kept in close contact with the thermal transfer dye-donating material during thermal transfer, part of the dye-donating material which is in the form of a thin sheet leaves its original position relative to the image-receiving material and produces wrinkles. These wrinkles cause streaks in the resulting transferred image, i.e., the image has recording unevenness or abnormality. Although incorporation of a fluorine-containing compound is effective in preventing heat fusion and improves the close-contact property, fluorine-containing high-molecular weight compounds which particularly improve the close-contact property have poor compatibility with various high-molecular weight compounds which are useful as image-receiving material, especially with polyester resins. Because of this drawback, there has been the problem that with an image-receiving material having a coating of a blend of such a fluorine-containing high-molecular weight compound and a polyester series resin, the coating suffers phase separation on the surface thereof, resulting in formation of minute specks, loss of gloss, etc.